Concurrent habitual use of alcohol and tobacco lead to numerous short- and long-term health consequences (cardiovascular, pulmonary, and cancer) and premature deaths in our country each year. While smoking rates in the general population have decreased substantially over the last several decades, they remain high among heavy alcohol drinkers. While clients in smoking cessation treatment are advised to reduce or quit drinking, little is known about the nature of alcohol's acute effects on smoking urges in the absence of actual smoking or direct smoking cues, both of which may exert effects on smoking urge. Further, prior studies have suggested that men may smoke more for interoceptive than exteroceptive factors compared to women; however, it is not known whether this difference may also extend to alcohol-related cigarette smoking behaviors. The overall objective of the proposed 2 studies is to systematically investigate the subjective and physiological effects of acute alcohol vs. placebo consumption on smoking-related behaviors in male and female habitual drinker-smokers. The first study will examine dose and time course effects of alcohol compared to placebo on cigarette craving and the subjective reinforcing value of cigarettes (in the absence of concurrent smoking). The second study will differentiate whether alcohol-induced effects on smoking urge and behavior are related to nicotine or non-nicotine factors by examining choice consumption of nicotinized vs. denicotinized cigarettes during alcohol and placebo beverage conditions. Both studies will examine potential individual difference factors, such as male sex and heavy drinking levels, which may mediate the relationship between treatment (alcohol or placebo) and outcome (smoking urges and behavior). Understanding the potential unique biobehavioral mechanisms underlying alcohol and nicotine interactions for chronic habitual users of both substances may help to tailor early prevention and treatment programs to reduce concurrent heavy use of both substances. [unreadable] [unreadable]